Almost none of the reputed schools offer admission to international students without IELTS or TOEFL. For UK, IELTS is also used as a proof for proficiency in English language by British High Commission of granting a visa. If you have good scores in your English subject tests in high school or college, you may be granted a visa, but they may still call you for an interview.

These are the three universities I found from UK which may offer conditional admission without IELTS.
Bristol University
The University of Sheffield
Middlesex University

After admitting into these universities, you’ll be asked to join an ESL program course. You’ll require to take an English language test after you complete the course.